IPA: //ˈkæləsnəs//
KK: /ˈkæləsnəs/
The quality of being emotionally insensitive or unfeeling towards others.
His callousness towards the suffering of others shocked everyone around him.
Callousness → It is formed from "callous" (from Latin *callosus*, meaning hard or thick-skinned) and the suffix "-ness" (meaning the state or quality of). The word "callousness" refers to the state of being emotionally insensitive or unfeeling, akin to being hard or thick-skinned.
Think of being 'hard' or 'thick-skinned' ('callous') to remember that 'callousness' means a lack of emotional sensitivity.